Trip.com complaint: Problematic check-in and undue fees – I do not recommend Trip.com!!

I bought two tickets on the route Dublin-Venice and Venice-Dublin by Raynair through Trip.com for the month of Nov22.
On the way there, I already had a problem with the early online check-in both through the website and the Trip.com app, but I went to the Raynair counter at the airport in advance and managed to solve it and had the boarding passes issued free of charge.
But on the return Venice-Dublin the same problem occurred. Through Trip.com platforms, there were consecutive errors at check-in and it was not possible to proceed with the procedure. Also the information for these flights was not on the Raynair website due to some failure in the communication between the systems, which also did not allow me to try to check-in there.
I arrived super early at the airport to try to resolve it again at the Ryanair counter. Upon arriving and explaining to the attendant, I was informed that it was not possible to access the system and that I should return to the counter 2 hours in advance, but at no time was it said that there would be a fee to check-in there.
Upon returning at the requested time, the attendant informed that both I and the other passenger would have to pay €55 each.
I tried to argue in various ways that it wasn’t my problem that I didn’t check in earlier and that it was unfair to charge me a fee of €55 per person, even more so when I paid around €30 for the tickets. However, there was no agreement, I ended up paying the fee and they advised me to try to talk to the purchase partner.
Since then, I have tried to contact them several times through the Trip.com chats to request a refund of this unfair and undue fee, but always with a different deadline and never with a satisfactory response.
I make this complaint to express my indignation with what happened. First, because it wasn’t my fault that I couldn’t perform the early check-in online, it was simply unfeasible and unavailable in all my attempts. Second, the fee charged is absurd, as it was more expensive than the value of the flight.
I’ve flown several times with Ryanair and I’ve never had this problem before with other partners.